In order to reduce a back-reflected light from an output facet when a laser light is output from a semiconductor laser element, a bending waveguide is widely used, which bends at about 7 degrees with respect to the output facet, for example. With the help of the bending waveguide, the back-reflected light returning to a resonator of the semiconductor laser element is reduced, so that a stable laser light can be output.
On the other hand, in a conventional semiconductor laser module in which light output from a semiconductor laser module is guided to an optical fiber to output the light through the optical fiber, a part of the output laser light is branched by a beam splitter or the like, and wavelength locking control is performed using an optical power monitor and a wavelength monitor that monitors the optical power of a predetermined wavelength. In this case, when the beam splitter is provided to each of the optical power monitor and the wavelength monitor, the number of optical components increases, which impedes downsizing of the semiconductor laser module. Therefore, a technique is disclosed in which an optical power monitor and a wavelength monitor are disposed in parallel on the light flux of the light branched by the beam splitter, and the branched light are divided in the optical axis direction to be respectively received by the optical power monitor and the wavelength monitor (see Patent Document 1).